Poor computer desk design suffocates Seasonic PSU

quietdragon · Post by **quietdragon** » Fri Jan 30, 2004 11:15 pm

My noisy PC is gradually transforming into a quiet machine. I recently swapped out my Enermax EG-365P VE for a Seasonic SS-300FS (non Active PFC).

The Enermax unit has two fans, and I must admit I didn't think it was all that bad. Maybe it was just my system, but I've spent my time changing the CPU HS fan, and changing the HD and only now is the unit quiet enough that the PSU becoming a concern.

The PC is housed under a small Ikea computer desk. There's a little shelf attached under the desk that holds the PC. Behind the shelf, the upper part of the back of the desk is obstructed by a support.

After swapping the PSU, I shoved the PC back its into usual position and thought nothing more of it.

About 1.5 hours later, I return to find the PC has hung at idle! Pressing the reset button would initiate a reboot, but the machine would not boot.

I pulled the PC out from under the desk, removed the cover, peered around, restarted it, and it booted fine. Left out, it ran for the rest of the evening!

My theory is that the shelf under the desk, and the rear desk support conspire to restrict the lower airflow generated by the Seasonic fan. The PSU got too warm, and couldn't supply the power required. When I opened the case, and fiddled around, it probably got cool enough to recover.

The Enermax, with its more aggressive twin fan design, seemed to do ok in that position.

Tonight, I removed the shelf, and repositioned the PC so that the PSU vent under the rear desk support.

So far, so good.

Post by **Ralf Hutter** » Sat Jan 31, 2004 5:27 am

That's a fairly common problem with those computer desks where the case sits in a cubby-hole. I've counseled many people to remove parts of the back wall for ventilation purposes, some listen, some don't.

Bluefront · Post by **Bluefront** » Sat Jan 31, 2004 5:30 am

Yeah.....you were suffering an extreme case of back-pressure on the PSU output. This was made worse when you changed to a PSU with a less powerful fan setup.

There is one thing you could have done.....rig up a duct that deflects the output downward. This would lessen back-pressure quite a bit. But if you were using a rear case fan to blow in, you would also have to separate the two air -streams.

Your solution was the easier route.....